Polymerizable compositions for making optical lens with high refractive index and high abbe number, and resulting lens

ABSTRACT

The present invention relates to polymerizable compositions for the manufacture of optical lenses with a high refractive index and a high Abbe number, and optical lenses comprising these compositions.

This application is a continuation of international application numberPCT/FR99/00726 filed Mar. 29, 1999, which is a continuation of FrenchApplication No. 98/04190 filed Apr. 3, 1998.

The subject-matter of the present invention is novel polymerizablecompositions for the manufacture of optical lenses with a highrefractive index and a high Abbe number and the optical lenses, inparticular ophthalmic lenses, obtained from these compositions.

The term “optical lens with a high refractive index” means an opticallens with a refractive index of greater than or equal to 1.55 andpreferably greater than 1.57.

Novel polymerizable compositions according to the invention arepreferably of use in the manufacture of spectacle glasses.

An ophthalmic lens with a high refractive index must have all thefollowing characteristics:

a high transmission (transmission generally of greater than 85% andpreferably of greater than or equal to 90%), with an absence of oroptionally a very low light scattering,

a high Abbe number of greater than or equal to 30 and preferably ofgreater than or equal to 35, in order to avoid chromatic aberrations,

a low yellowing index and an absence of yellowing over time,

good impact strength (in particular according to the CEN and FDAstandards),

good suitability for various treatments (shock-proof primer, anti-glareor hard coating deposition, and the like) and in particular goodsuitability for colouring,

a glass transition temperature value preferably of greater than or equalto 80° C. and better still of greater than 90° C., preferably of between90 and 110° C.

In addition, the polymerizable compositions must also be easy to processindustrially.

In particular, it is desirable for the polymerizable compositions to beable to be quickly polymerized, in particular by photopolymerization.

Patent Document WO 96/38486 discloses polymerizable compositions for themanufacture of optical lenses with a high index and a high Abbe numbercomprising 20 to 60% by weight of an acrylate or methacrylate monomerderived from a polycyclic olefin, in particular an acrylate ormethacrylate derivative of tricyclodecane, 15 to 60% by weight of a di-or polythiol, 5 to 50% by weight of a divinyl or polyvinyl monomer, thevinyl groups of which do not form a (meth)acrylic group, and 0 to 20% byweight of a polymerizable comonomer which can be chosen frommethacrylates, acrylates, thiomethacrylates, thioacrylates, vinyls,vinyl ethers, allyls, epoxides and the like.

Although it is indicated that the polymerizable compositions of thisdocument can be polymerized thermally and/or by UV irradiation, all theimplementational examples report a thermal curing, the duration of whichis particularly lengthy (8 hours).

Patent Document WO 97/44372 discloses a polymerizable composition forthe manufacture of ophthalmic lenses which comprises 2.5 to 100% of adivinyl ester cyclic monomer, 5 to 30% by weight of a di- or polythiolmonomer and, optionally, 1 to 40% by weight of a thiodiacrylate or-dimethacrylate monomer.

A subject-matter of the present invention is therefore a compositioncomprising polymerizable monomers for the manufacture of ophthalmiclenses with a high refractive index and a high Abbe number which iseasily polymerizable, in particular which is easily photopolymerizable.

The composition comprising polymerizable monomers according to theinvention comprises:

(A) at least one polythio(meth)acrylate monomer;

(B) at least one monomer with a high Abbe number comprising at least twopolymerizable groups, preferably two to four polymerizable groups, andat least one bridged cyclic constituent unit, the bridged cyclicconstituent unit or units not being bonded directly to an oxygen atom;

(C) at least one polythiol monomer; and, optionally,

(D) at least one other monomer which is copolymerizable with themonomers (A), (B) and (C), the composition being devoid of any othermonomer comprising one or more vinyl functional groups, other than(meth)acrylic and thio(meth)acrylic functional groups, which isdifferent from the monomers (B).

By definition, a thio(meth)acrylate monomer is a monomer comprising the

group, R₅ having the meaning which appears hereinbelow.

The monomer (A) is preferably a dithio(meth)acrylate.

The monomer (A) is, preferably again, an aliphatic monomer.

A first class of polythio(meth)acrylate monomers suitable for thecompositions according to the invention corresponds to the formula:

in which:

R₄ represents a linear or branched, monovalent or polyvalent, aliphatichydrocarbonaceous radical or a monovalent or polyvalent, aromatic orheterocyclic group bonded directly to the sulphur atom of thethio(meth)acrylate group or groups by a nucleus or via a linear alkylchain, it being possible for the R₄ radical to comprise, in its chain,one or more groups chosen from —O—, —S— or

R₅ represents hydrogen or —CH₃; and

n² is an integer from 1 to 6, preferably from 1 to 3.

Mention may be made, among monovalent R₄ radicals, of linear or branchedC₁ to C₅ alkyl radicals or radicals of formula:

in which:

R₆ and R₇ are, independently of one another, H or a linear or branchedC₁-C₅ alkyl radical;

R₈ is a linear or branched C₁-C₅ alkyl radical, a C₇-C₁₀ aralkyl radicalor a C₆-C₁₂ aryl radical which is optionally substituted, in particularby alkyl and/or halogen groups; and

n is an integer from 1 to 4.

Mention may be made, among preferred monovalent R₄ radicals, of:

Monomers of formula (I) for which n²=1 and which are as defined aboveare disclosed, inter alia, in U.S. Pat. No. 4,606,864, JP-63316766 andEP-A-0,384,725.

Mention may be made, among divalent R₄ radicals coming within thecontext of the monomers of formula (I), of linear or branched C₂ to C₁₀alkylene radicals which can comprise, in their chain, one or more —O—,—S— or

groups, alkylidene radicals of formula

in which R₉ and R₁₀ are C₁-C₅ alkyl radicals, radicals of formula:

in which R₁₁ and R₁₂ are linear or branched C₁-C₅ alkylene groups whichcan comprise one or more —O—, —S— or

groups in their chains, X″ is chosen from C₁-C₅ alkyl radicals andhalogens, and n⁴ is an integer from 0 to 4, and radicals of formula:

in which R₁₃ and R₁₄ are linear or branched C₁ to C₅ alkylene radicalswhich can comprise, in their chain, one or more —O—, —S— or

groups and t and s are equal to 0 or 1.

Mention may be made, among preferred divalent R₄ radicals, of thefollowing radicals:

where q′ is an integer from 1 to 8;

 CH₂CH₂X_(u)CH₂CH₂—

where X is —O— or —S— and u is an integer from 1 to 4;

CH₂_(u′)S(CH₂)_(v′)_(z′)CH₂_(w′),

where z′ is equal to 0 or 1 and u′, v′ and w′ are integers from 2 to 6;

where u″ and v″ are integers from 1 to 4,

Particularly preferred divalent R₄ radicals are:

Divalent monomers of formula (I) are disclosed, inter alia, in PatentsEP-A-273,661, EP-A-273,710 and EP-A-384,725.

Mention may be made, among trivalent R₄ radicals of the monomers offormula (I), of C₃ to C₁₀ alkyltriyl radicals which can comprise, intheir chain, one or more —O—, —S— or

groups, trivalent alkylaryl radicals, the alkyl chains of which compriseone or more —S— or —O— groups, and trivalent aryl groups.

Mention may be made, among trivalent R₄ radicals or R₄ radicals with ahigher valency, of:

and the like.

Mention may be made, among monomers of formula (I) recommended in thepresent invention, of:

S-2-acryloyloxyethyl thio(meth)acrylate,

S-2-methacryloyloxyethyl thio(meth)acrylate,

1,2-bis[(meth)acryloylthio)]ethane,

1,2-bis[(meth) acryloylthio]propane,

1,3-bis[(meth) acryloylthio]propane,

1,4-bis[(meth) acryloylthio]butane,

bis[2-(meth)acryloylthioethyl]ether,

bis[2-(meth)acryloylthioethyl]sulphide,

bis[2-(meth)acryloylthioethoxy]methane,

bis[2-(meth)acryloylthioethylthio]methane,

1,2-bis[2-(meth) acryloylthioethoxy]ethane,

1,2-bis[2-(meth)acryloylthioethylthio]ethane,

bis[2- (2-(meth) acryloylthioethoxy)ethyl]ether,

bis[2-b(2-(meth)acryloylthioethylthio)ethyl]sulphide,

1,4-bis[(meth)acryloylthio]benzene,

1,4-bis[(meth)acryloylthiomethyl]benzene,

benzylthioethyl thio(meth)acrylate,

1,4-bis[(meth)acryloylthio]-2,3-dimethylthiobutane,

1,2,3-tris[(meth)acryloylthioethylthio]propane, and

bis[(meth)acryloylthiophenyl]sulphide,

where R₅ represents a hydrogen atom or a methyl group.

Another class of thio(meth)acrylic monomers suitable in the compositionscomprising monomers according to the invention corresponds to theformula:

in which R₅ represents H or CH₃, R₁₅ represents an optionally branchedC₂-C₁₂ alkylene group, a C₃-C₁₂ cycloalkylene group, a C₆-C₁₄ arylenegroup or a C₇-C₂₆ alkarylene group, it being possible for thecarbonaceous chain of the R₁₅ group to be interrupted by one or moreether or thioether groups, and n⁵ is an integer from 1 to 6.

Such monomers are disclosed in U.S. Pat. No. 5,384,379.

A recommended polythiomethacrylate monomer isbis(2-methacryloylthioethyl) sulphide (BMTES).

The polythiomethacrylate monomer or monomers generally constitute from10 to 60% by weight, preferably 25 to 60% by weight, with respect to thetotal weight of polymerizable monomers present in the composition.

The monomers (B) with a high Abbe number suitable for the compositionsof the invention are monomers comprising at least two, preferably two tofour, polymerizable groups and at least one bridged cyclic constituentunit, the bridged cyclic constituent unit or units not being bondeddirectly to an oxygen atom.

The bridged cyclic constituent units are preferably chosen fromnorbornenyl and dicyclopentenyl radicals and their divalent hydrogenatedderivatives.

The polymerizable groups are preferably (meth)acrylic orthio(meth)acrylic groups or bridged cyclic groups comprising anintracyclic ethylenic double bond or a linear or branched aliphaticresidue comprising an ethylenic unsaturation, preferably a vinyl orethylidene group bonded directly to a carbon of the ring.

The bridged cyclic polymerizable groups can be chosen from the groups offormulae:

where n is an integer from 0 to 5 inclusive, k is an integer from 0 to 3inclusive and j is an integer from 0 to 10 inclusive, and

where n is an integer from 0 to 5 inclusive, k′ is an integer from 0 to2 inclusive and j′ is an integer from 0 to 10 inclusive, Q represents a—C(R′)₂—, —O—, —S—, —NR′— or —SO₂— group, with R′ denoting H or a C₁-C₃alkyl radical, preferably a hydrogen atom or —CH₃, and R is a hydrogenatom or a C₁-C₃ alkyl radical, preferably —CH₃.

Mention may be made, among preferred groups above, of groups offormulae:

in which the R radicals represent, independently of one another, ahydrogen atom or a C₁-C₃ alkyl group, for example methyl, preferably ahydrogen atom, Q is a divalent radical chosen from —C(R′)₂—, —O—, —S—,—SO₂— or —NR′—, where R′ is a hydrogen atom or a C₁-C₃ alkyl radical,preferably a methyl radical, Q preferably being a —CH₂— radical, n=0 to5 and m=0 to 8.

It is obvious that, when the functional groups of the monomer (B) arethio(meth)acrylate groups, the monomers (A) and (B) present in thecomposition are different monomers.

More preferably, a monomer with a high Abbe number is chosen, therefractive index of which is at least 1.56.

A first class of monomers (B) with a high Abbe number is composed ofmonomers comprising polymerizable (meth)acrylic or thio(meth)acrylic endgroups comprising, in their chains, a bridged cyclic constituent unit asdefined above.

Among these monomers with a high Abbe number, recommended monomerscorrespond to the formula:

in which Q and R₅ are defined as above, X represents —O— or —S—, a=1-3,b=1-3, g and g′ vary from 0 to 6, and G and G′ are divalent groupschosen from one or more of the following groups:

in which r=1-4.

Preferred compounds of this class are di(meth)acryloyls ofhydroxymethyltricyclodecane and dithio(meth)acryloyls ofhydroxymethyltricyclodecane.

A particularly recommended compound is the compound of formula:

Compounds corresponding to the above formula (III) are disclosed inPatent Document WO 96/38486.

Another class of monomers (B) which is recommended are monomerscomprising polymerizable bridged cyclic end groups, in particularnorbornenyl and dicyclopentenyl groups.

More particularly, compounds of this class correspond to the generalformula:

ZA)_(n)a  (IV)

in which n^(a) is an integer from 2 to 4 and A is a radical chosen fromradicals of formulae:

in which Q represents —C(R′)₂—, —O—, —S—, —SO₂— and —NR′—, where R′represents H or a C₁-C₃ alkyl radical, R represents hydrogen or a C₁-C₃alkyl radical, preferably CH₃, n=0-5 and m=0-8, and

(I) when n^(a)=2, Z represents a divalent radical of a formula:

in which formulae X represents —-O— or —S—, G₁ and G′₁ areC_(n′)H_(2n′)O_(m′)groups, with n′=1 to 5, preferably n′=2, and m′varies from 0 to 10, or a C₁-C₅ alkylene group, Z₁ is chosen fromdivalent radicals of formulae:

in which formulae Q is defined as above, B₁ represents —C(R₂)₂— or —S—,R₂ is a C₁-C₃ alkyl radical, preferably —CH₃, x₁=0 or 1, Y₁ represents,independently of one another, Br, Cl or H, y₁ is an integer from 0 to 4,the R_(b) groups denote, independently of one another, a CH₂_(q)group, q is an integer from 1 to 4, preferably equal to 1 or 2, and p isan integer from 0 to 4, preferably from 0 to 2; and

Z₂ is a divalent radical chosen from radicals of formulae:

where Q, R_(b) and p are defined as above and Z₃ is a divalent radicalchosen from:

where Q and x₁ are defined as above;

(II) when na=3, Z represents a trivalent radical chosen from:

where R_(b) and p are defined as above and R_(c) represents H or a C₁-C₃alkyl group, preferably —CH₃; and

(III) when n^(a)=4, Z represents a tetravalent radical chosen from thefollowing radicals:

CR₃₄,

where R₃ is a C₁-C₅ alkylene radical or a SR_(b)_(p)S— radical whereR_(b) and p are defined as above.

Preferred monomers of this class correspond to the formula:

where R is H or CH₃, X is —O— or —S—, B is —S— or

n′ and n″=1 to 5 and m′ and m″ vary from 0 to 10. Preferably, 3≦m′+m″≦5and n′ and n″=2.

A monomer of this type which is particularly recommended is the monomerof formula:

Bisphenol A 2-ethoxylate dinorbornene-carboxylate.

Polymerizable monomers of this type are disclosed, inter alia, in PatentDocument WO 88/02902.

Mention may also be made, among preferred monomers comprising endpolycycloalkenyl groups, of monomers of formula:

where R═H or CH₃, R_(b) is as defined above, preferably a propyleneradical, p′ is an integer from 1 to 3, preferably equal to 2, and p″ isan integer equal to 0 or 1.

A recommended monomer of formula (VIII) is the monomer of formula:

(MESDTMN) or mercaptoethyl sulphide dithiometh-norbornenecarboxylate.

Mention may be made, among monomers of formula (VI) above, of monomersin which Z₂ represents the following groups:

Such monomers, and the process for their preparation, are disclosed inPatent Document JP-81 51360.

Mention may be made, among recommended trivalent monomer constituentscomprising end polycycloalkenyl groups, of monomers of formulae:

Polymerizable monomers (B) represent 5 to 50%, preferably 10 to 40%, byweight with respect to the total weight of polymerizable monomerspresent in the composition.

The third essential constituent of the compositions according to theinvention is a polymerizable polythiol monomer (C).

Polythiol monomers which are suitable for the compositions according tothe present invention are well known in the art and can be representedby the formula R₁(SH)_(n) ¹ in which n¹ is an integer of 2 or more,preferably from 2 to 5, and R₁ is an aliphatic, aromatic or heterocyclicradical.

The polythiol compound is preferably a dithiol, trithiol or tetrathiolcompound, in particular a polythiol with a high Abbe number.

These polythiol compounds are well known in the art and are disclosed,inter alia, in Document EP 394,495.

Mention may be made, among dithiols of use in the present invention, of9,10-anthracenedimethanethiol, 1,11-undecanedithiol,4-ethylbenzene-1,3-dithiol, 1,2-ethanedithiol, 1,8-octanedithiol,1,18-octadecanedithiol, 2,5-dichlorobenzene-1,3-dithiol,1,3-(4-chlorophenyl)propane-2,2-dithiol, 1, 1-cyclohexanedithiol,1,2-cyclohexanedithiol, 1,4-cyclohexanedithiol, 1,1-cycloheptanedithiol,1,1-cyclopentanedithiol, 4,8-dithiaundecane-1,11-dithiol,dithiopentaerythritol, dithiothreitol, 1,3-diphenylpropane-2,2-dithiol,1,3-dihydroxy-2-propyl 2′,3′-dimercaptopropyl ether, 2,3-dihydroxypropyl2′,3′-dimercaptopropyl ether, 2,6-dimethyloctane-2,6-dithiol,2,6-dimethyloctane-3,7-dithiol, 2,4-dimethylbenzene-1,3-dithiol,4,5-dimethylbenzene-1,3-dithiol, 3,3-dimethylbutane-2,2-dithiol,2,2-dimethylpropane-1,3-dithiol,1,3-di(4-methoxy-phenyl)propane-2,2-dithiol,3,4-dimethoxybutane-1,2-dithiol, 10,11-dimercaptoundecanoic acid,6,8-dimercaptooctanoic acid, 2,5-dimercapto-1,3,4-thiadiazole,2,2′-dimercaptobiphenyl, 4,4′-dimercapto-biphenyl,4,4′-dimercaptobibenzyl, 3,4-dimercapto-butanol, 3,4-dimercaptobutylacetate, 2,3-dimercapto-1-propanol, 1,2-dimercapto-1,3-butanediol,2,3-dimercaptopropionic acid, 1,2-dimercaptopropyl methyl ether,2,3-dimercaptopropyl 2′,3′-dimethoxypropyl ether, 3,4-thiophenedithiol,1,10-decanedithiol, 1,12-dodecanedithiol,3,5,5-trimethylhexane-1,1-dithiol, 2,5-toluenedithiol,3,4-toluenedithiol, 1,4-naphthalenedithiol, 1,5-naphthalenedithiol,2,6-naphthalenedithiol, 1,9-nonanedithiol, norbornene-2,3-dithiol,bis(2-mercaptoisopropyl) ether, bis(11-mercaptoundecyl) sulphide,bis(2-mercaptoethyl) ether, bis(2-mercaptoethyl) sulphide,bis(18-mercaptooctadecyl) sulphide, bis(8-mercaptooctyl) sulphide,bis(12-mercaptodecyl) sulphide, bis(9-mercaptononyl) sulphide,bis(4-mercaptobutyl) sulphide, bis(3-mercaptopropyl) ether,bis(3-mercaptopropyl) sulphide, bis(6-mercaptohexyl) sulphide,bis(7-mercaptoheptyl) sulphide, bis(5-mercaptopentyl) sulphide,2,2-bis(mercaptomethyl)acetic acid, 1,1-bis(mercaptomethyl)cyclohexane,bis(mercaptomethyl)durene, phenylmethane-l,l-dithiol, 1,2-butanedithiol,1,4-butanedithiol, 2,3-butanedithiol, 2,2-butanedithiol,1,2-propanedithiol, 1,3-propanedithiol, 2,2-propanedithiol,1,2-hexanedithiol, 1,6-hexanedithiol, 2,5-hexanedithiol,1,7-heptanedithiol, 2,6-heptanedithiol, 1,5-pentanedithiol,2,4-pentanedithiol, 3,3-pentanedithiol, 7,8-heptadecanedithiol,1,2-benzenedithiol, 1,3-benzenedithiol, 1,4-benzenedithiol,2-methylcyclohexane-1,l-dithiol, 2-methylbutane-2,3-dithiol, ethyleneglycol dithioglycolate or ethylene glycol bis(3-mercaptopropionate).Mention may be made, among trithiols, of 1,2,3-propanetrithiol,1,2,4-butanetrithiol, trimethylolpropane trithioglycolate,trimethylolpropane tris(3-mercaptopropionate), pentaerythritoltrithioglycolate, pentaerythritol tris(3-mercaptopropionate),1,3,5-benzenetrithiol and 2,4,6-mesitylenetrithiol.

Mention may also be made, among polythiols of use in the compositions ofthe present invention, of neopentanetetrathiol,2,2-bis(mercaptomethyl)-1,3-propanedithiol, pentaerythritoltetrakis(3-mercaptopropionate), 1,3,5-benzenetrithiol,2,4,6-toluenetrithiol, 2,4,6-methylenetrithiol and polythiolscorresponding to the formulae:

(HSCH₂CH₂COOCH₂)₃CC₂H₅ (TMPT), and4-mercaptomethyl-3,6-dithia-1,8-octanedithiol.

The polythiol monomer (C) generally represents 10 to 60% by weight,preferably 20 to 50% by weight, with respect to the total weight ofpolymerizable monomers present in the composition.

The compositions according to the invention can also comprise otherpolymerizable monomers (D), with the exception of monomers comprisingvinyl functional groups other than (meth)acrylate or thio(meth)acrylategroups.

Mention may be made, among these other monomers, of monomers or mixturesof monomers of formula:

in which R₅ independently represents H or CH₃ and m₂+n₂ has a mean valuefrom 0 to 20 inclusive.

Preferred monomers of formula (IX) are compounds in which R₅=CH₃ andm₂+n₂=2.6 (EBADMA), m₂+n₂=4 (DBADMA) and m₂+n₂=10 (OBADMA).

The particularly preferred monomer is bisphenol Abis(diethoxymethacrylate) (DBADMA).

These monomers represent from 0 to 60% by weight, preferably 10 to 50%by weight, of polymerizable monomers present in the composition.

The polymerizable compositions according to the invention can alsocomprise additives conventionally used in polymerizable compositions forthe moulding of optical articles, in particular spectacle glasses, inconventional proportions, namely inhibitors, colorants, UV absorbers,fragrances, deodorants, antioxidants and anti-yellowing absorbents.

Mention may be made, as preferred examples of antioxidizing agents, oftriphenylphosphine (TPP) and Irganoxe® 1010 (pentaerythritoltetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (CG1010).

Fragrances make it possible to mask the odour of the compositions, inparticular during surface working operations.

The compositions according to the invention generally comprisepolymerization initiators, preferably photoinitiators or mixtures ofphotoinitiators and of thermal initiators, in a proportion of 0.001 to5% by weight with respect to the total weight of polymerizable monomerspresent in the composition.

Mention may in particular be made, among photoinitiators which can beused in the polymerizable compositions according to the invention, of2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, alkylbenzoylethers, the photoinitiator sold by the Company Ciba-Geigy under the nameCGI 1700, which is a 25/75 mixture of a compound of formula:

and of a compound of formula:

and the photoinitiator CGI 1850 sold by the Company Ciba-Geigy, which isa mixture (50/50) (by weight) of compound A and of Irgacure® 184 offormula:

As indicated above, the preferred polymerizable compositions accordingto the invention are photopolymerizable compositions comprising one ormore photoinitiators.

More preferably, the polymerizable compositions according to theinvention are photo- and thermo-polymerizable compositions comprisingboth a polymerization photoinitiator and a polymerization thermalinitiator.

Thermal polymerization initiators are compounds which are well known inthe art and mention may be made, among them, of peroxides, such asbenzoyl peroxide, cyclohexyl peroxydicarbonate, isopropylperoxydicarbonate and t-butyl peroxy(2-ethylhexanoate).

Monomers of formula (IV) can be synthesized either by a Diels-Alderreaction between a compound comprising two or more (meth)acrylate orthio(meth)acrylate functional groups and a cycloalkene, such ascyclopentadiene or norbornadiene, or by addition of thiol/ene typebetween a polythiol compound and an ene compound, such ascyclopentadiene, norbornadiene, vinylnorbornene or ethylidenenorbornene.

The polythiol compound and the ene compound are reacted in proportionscorresponding substantially to one thiol group of the polythiol compoundor compounds per mole of ene compound.

By way of example, the scheme is shown below for the synthesis ofmonomers with a high Abbe number according to the invention from5-vinyl-2-norbornene or 5-ethylidene-2-norbornene with a dithiol:

where W is an aliphatic or aromatic radical.

EXAMPLES OF THE SYNTHESIS OF MONOMERS OF FORMULA (IV) BY THE DIELS-ALDERREACTION 1) Synthesis of bisphenol A 2-ethoxylatedinorbornenecarboxylate (EBPADN)

700 g of bisphenol A 2-ethoxylate diacrylate (EBPADA), Sartomer® SR 349,are introduced into a three-necked flask equipped with a mechanicalstirrer, a dropping funnel for introducing reactant and a condenser. TheEBPADA had a refractive index n_(D) at 21° C. at 1.5465 and a relativedensity of 21° C. of 1.1478.

The acrylic monomer is then degassed by means of a roughing vacuum pumpand then dinitrogen is introduced into the three-necked flask. 198 g offreshly cracked cyclopentadiene (CPD) are then added dropwise via thedropping funnel. The temperature of the reaction mixture rises as theDiels-Alder reaction between the cyclopentadiene and the diacrylatetakes place. The excess cyclopentadiene is then discharged byalternating the vacuum by means of the roughing vacuum pump and theintroduction of dinitrogen into the three-necked flask. Discharge of theexcess cyclopentadiene is brought to completion by means of a rotaryevaporator. If the presence of impurities is observed, the monomerobtained is then filtered by means of a vacuum flask.

The expected product, EBPADN, is obtained with a yield of 93.53%, thisproduct having a molar mass of 556, a refractive index n_(D) at 21° C.of 1.5497 and a relative density at 21° C. of 1.1569.

2) Syntheses of trimethylolpropane trinorbornenecarboxylate (TMPTN)

The synthesis is carried out as in the preceding synthetic example butwithout final discharge of the excess CPD by means of a rotaryevaporator, in order to prevent the product from setting solid.

In this synthesis, use was made of 338 g of trimethylolpropanetriacrylate, molar mass 296, refractive index n_(D) at 21° C. of 1.4752and relative density at 21° C. of 1.10067, which product is sold by theCompany Cray Valley under the reference SR 351, and 217 g ofcyclopentadiene were added.

The expected product, TMPTN, was obtained with a yield of greater than95%, this product having a molar mass of 494, a refractive index n_(D)at 21° C. of 1.511 and a relative density at 21° C. of 1.146.

3) Synthesis of mercaptoethyl sulphide dithiomethnorbornenecarboxylate(MESDTMN)

The synthesis is carried as in the first synthetic example, using 211 gof bis[(2-methacryloylthio)ethyl] sulphide (BMTES); molar mass 282,n_(D) at 21° C. 1.5745, relative density 21° C. 1.177, as startingmaterial and 100 g of cyclopentadiene.

The expected product (MESDTMN) is obtained with a yield of greater than95%, this product having a molar mass of 414, a refractive index n_(D)at 21° C. of 1.5683 and a relative density at 21° C. of 1.1588.

It should be noted that the reactivity of a thiomethacrylate is muchgreater than that of the corresponding methacrylate (which would haverequired a catalyst of the Lewis acid type for the reaction).

4) Examples of synthesis from 5-vinyl-2-norbornene and from5-ethylidene-2-norbornene Synthetic Example 1

12.6 g of 5-vinyl-2-norbornene (purity 95%) are introduced into areactor equipped with a condenser, a magnetic stirrer and a nitrogenfeed allowing the synthesis to be carried out under an inert atmosphere.Heating is carried out to 70° C. and 8.5 g of 2-mercaptoethyl sulphideare added over 30 minutes using a dropping funnel. During the addition,exothermicity is observed and the temperature of the reaction mixturereaches 165° C. The reaction is monitored by infrared spectroscopy untilthe —S—H band at 2571 cm⁻¹ has completely disappeared. The productexhibits a refractive index of 1.571 at 25° C.

Synthetic Example 2

The synthesis is carried out in the same way as in Synthetic Example 1,using 11.2 g of 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol (purity93%) and 15.2 g of 5-vinyl-2-norbornene. The maximum temperature reachedduring the addition of the thiol is 79° C. The product obtained exhibitsa refractive index of 1.579 at 25° C.

Synthetic Example 3

The synthesis is carried out in the same way as in Synthetic Example 1,using 12.2 g of pentaerythritol tetrakis(3-mercaptopropionate) and 12.6g of 5-vinyl-2-norbornene. The maximum temperature reached during theaddition of the thiol is 134° C. The product obtained exhibits aviscosity of 0.48 Pa·s at 25° C. and a refractive index of 1.531 at 25°C.

Synthetic Example 4

The synthesis is carried out in the same way as in Synthetic Example 1,using 12.2 g of pentaerythritol tetrakis(3-mercaptopropionate) and 12 gof 5-ethylidene-2-norbornene (purity 99a). The maximum temperaturereached during the addition of the thiol is 95° C. The product obtainedexhibits a viscosity of 7.66 Pa·s at 25° C. and a refractive index of1.5445 at 25° C.

Compositions 1 to 6 of the invention were prepared by mixing theconstituents shown in Table I hereinbelow.

These compositions are subsequently cast in a two-part mould made ofinorganic glass and polymerized in order to obtain ophthalmic lensesaccording to the invention.

The refractive index at 21° C., the Abbe number, he relative density at21° C., the glass transition temperature, the suitability for colouringand the odour were determined with regard to these lenses.

In the following examples, except when otherwise indicated, all theparts and percentages are expressed by weight.

The percentages of adjuvants are generally expressed as percentage byweight with respect to the total weight of polymerizable monomerspresent in the composition.

Examples 1 to 5 and Comparative Examples C6 and C7

The compositions shown in Table I hereinbelow are prepared by simplephysical mixing.

TABLE I Examples Compositions (Parts by weight) 1 2 3 4 5 C6 C7 (A)BMTES 50 50 50 50 50 50 54 (B) DCPA 35 30 25 18 10 — — (C) PETG 15 20 1515 15 15 — TMTP — — — — — — 6 (D) DBADMA — — 10 17 20 35 40 UV 54110.10% 0.10% 0.10% 0.10% 0.10% 0.10% 0.10% CG 1010 0.10% 0.10% 0.10%0.10% 0.10% 0.10% 0.10% TPO 0.07% 0.07% 0.07% 0.07% 0.07% 0.07% 0.07%Irgacure ® 184 0.03% 0.03% 0.03% 0.03% 0.03% 0.03% 0.03% Perbutyl O0.10% 0.10% 0.10% 0.10% 0.10% 0.10% 0.10% BMTES:Bis(2-methacryloylthioethyl) sulphide DCPA: Diacryloyl ofhydroxymethyltricyclodecane PETG: Pentaerythritoltetrakis(thioglycolate) TMTP: Trimethylolpropanetris(3-mercaptopropionate) DBADMA:

UV 5411: 2-(2-Hydroxy-5-t-octylphenyl)benzo-triazole (UV absorber) CG1010: Pentaerythritoltetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidizingagent) TPO: 2,4,6-Trimethylbenzoyldiphenylphosphine oxide(photoinitiator) Irgacure 184: 1-Hydroxycyclohexyl phenyl ketone(photoinitiator) Perbutyl O: t-Butyl peroxy(2-ethylhexanoate) (thermalinitiator).

Each of the mixtures is poured into a mould made of inorganic glass forophthalmic lenses and then the moulds, thus filled, are exposed to UVirradiation.

The results of the measurements of the refractive indices, Abbe numbersand glass transition temperature (Tg) are given in Table II hereinbelow.

TABLE II Examples 1 2 3 4 5 C6 C7 Refractive index n_(D) 1.583 1.5861.586 1.588 1.594 1.593 n_(E) 1.588 1.591 1.59 1.592 1.599 1.598 Abbenumber v_(D) 43.58 44.18 41.9 43.02 39.73 37.43 v_(E) 43.91 44.5 42.2143.34 39.04 37.73 T_(g) >80° C. >80° C. >80° C. >80° C. >80° C. >80° C.

Examples 8 to 10

The following compositions shown in Table III hereinbelow are prepared.

TABLE III Compositions (parts by weight) 8 9 10 (A) BMTES 50 20 30 (B)EBPADN 30 30 30 (C) DMDS 20 — 10 MDO — 50 30 CGI 1850 0.15% 0.15% 0.15%TBPEH 0.1% 0.1% 0.1% UV 5411 0.07% 0.07% 0.07% EBPADN: Bisphenol A2-ethoxylate dinorbornene-carboxylate DMDS: Dimercaptodiethyl sulphideMDO: 4-Mercaptomethyl-3,6-dithia-1,8-octanedithiol CGI 1850: 50/50mixture of 1-hydroxycyclohexyl phenyl ketone and of

TBPEH: t-Butyl peroxy(2-ethylhexanoate).

The polymerizable mixtures 8 to 10 are poured into a mould made ofinorganic glass for ophthalmic lenses and then the moulds, thus filled,are exposed to UV irradiation.

The results of the measurements of refractive index, Abbe number,relative density and glass transition temperature (Tg) are shown inTable IV hereinbelow.

TABLE IV Examples 8 9 10 n_(D) 1.602 1.631 1.623 v_(D) 42 39 38 d₂₁ 1.221.25 — T_(g) (° C.) 89 90 75 Colourability Yes Yes Yes Odour No No No

Examples 11 to 13

The compositions shown in Table V hereinbelow were formulated as above.

The results of measurements of refractive index, Abbe number, relativedensity and glass transition temperature, as well as of a test ofexposure to sunlight for lenses moulded from these compositions, havealso been shown in Table V.

TABLE V Examples 11 12 13 BMTES 46 26 40 80N 22 23 — DCP — 30 — DCPA 12— 40 PETG 20 — — PDT — 20 20 TPO 0.1% 0.1% 0.1% Irgacure ® 184 0.1% 0.1%0.1% Thermal catalyst 0.1% 0.1% 0.1% n_(E) 1.5967 1.5945 1.6002 n_(D)1.5917 1.5986 1.5955 ν_(E) 40 41 42 ν_(D) 39 40 41 Relative density 1.31.24 1.27 Yellowing index (YI) 0.6 0.7 0.8 T_(g) >80° C. >80° C. >80° C.Test of exposure to sunlight Good Good Good 80N: BPE-80 N monomer, soldby the Company Shin Nakamura, of formula:

in which the mean value of m + n = 2.6. PDT: C(CH₂SCH₂CH₂SCH₂CH₂SH)₄DCP: Dimethacrylate of hydroxymethyltricyclodecane.

The yellowing index was measured according to ASTM Standard D 1425-63.

The test of exposure to sunlight consists of subjecting test specimensfor 200 hours to exposure to sunlight under the same conditions with aSuntest Hanau device emitting radiation of 24.4 W/m² in the 300-400 nmspectral region and in measuring the yellowing index (YI) before andafter irradiation. The test is regarded as positive (Good) if thedifference in YI is less than or equal to 1.

Measurement of the colourability

The measurement given is the value of the transmission, measured in thevisible region, of a glass with a centre thickness of 2 mm coloured bysteeping in an aqueous bath at 94° C., in which bath is dispersed a redpigment “Disperse Red 13” from the Company Eastman Kodak.

The Tg is measured by DMA (Dynamic mechanical analysis) on a flat testspecimen of 5.2 cm×1 cm×2 mm (thickness).

The test is carried out in 3-point bending.

Tg corresponds to the maximum of the ratio$\frac{E^{''}}{E^{\prime}}{\frac{\left( {{loss}{\quad \quad}{modulus}} \right)}{\left( {{storage}\quad {modulus}} \right)}.}$

Generally, unless otherwise indicated, all the tests were carried out onsamples with a thickness of 2 mm.

What is claimed is:
 1. Composition comprising polymerizable monomers,characterized in that it comprises: (A) 25 to 60% by weight based on thetotal weight of polymerizable monomers of at least onedithio(meth)acrylate monomer having formula:

in which R₄ is selected from the group consisting of linear or branchedC₂ to C₁₀ alkylene radicals which can comprise, in their chain, one ormore —O—, —S— or

 groups, alkylidene radicals of formula:

in which R₉ and R₁₀ are C₁-C₅ alkyl radicals, radicals of formula:

in which R₁₁ and R₁₂ are linear or branched C₁-C₅ alkylene groups whichcan comprise one or more —O—, —S— or

groups in their chains, X″ is chosen from C₁-C₅ alkyl radicals andhalogens, and n⁴ is an integer from 0 to 4, and radicals of formula:

in which R₁₃ and R₁₄ are linear or branched C₁ to C₅ alkylene radicalswhich can comprise, in their chain, one or more —O—, —S— or

groups and t and s are equal to 0 or 1, and R₅ represents H or —CH₃. (B)at least one monomer with a high Abbe number comprising 2 to 4polymerizable groups selected from (meth)acrylic or thio(meth)acrylicgroups, and at least one divalent bridged cyclic constituent unit, thebridged cyclic constituent unit or units not being bonded directly to anoxygen atom; (C) at least one polythiol monomer; and, optionally, (D) atleast one other monomer which is copolymerizable with the monomers (A),(B) and (C), the composition being devoid of any monomer comprising oneor more vinyl functional groups, other than (meth)acrylic andthio(meth)acrylic functional groups, which is different from themonomers (B), whereby the resulting polymer has an Abbe number of atleast 40 and a refractive index of at least 1.58.
 2. Compositioncomprising polymerizable monomers according to claim 1, characterized inthat the monomer (A) is bis(2-methacryloylthioethyl) sulphide (BMTES).3. Composition comprising polymerizable monomers according to claim 1,characterized in that, in the monomer (B), the bridged cyclicconstituent units are chosen from divalent hydrogenated derivatives ofnorbomenyl and dicyclopentenyl radicals.
 4. Composition according toclaim 1, wherein monomer (B) has the formula:

in which R₅ represents a hydrogen atom or a —CH₃ group, X represents —O—or —S—, G and G′ represent a

group, in which groups r=1-4, Q is a divalent radical chosen from—C(R′)₂—, —O—, —S—, —SO₂— or —NR′—, where R′ is a hydrogen atom or aC₁-C₃ alkyl radical, a and b are equal to 1 or 2 and g and g′ vary from0 to
 6. 5. Composition according to claim 4, characterized in that themonomer (B) corresponds to the formula:


6. Composition according to claim 1, wherein the monomer (B) represents5 to 50%, by weight with respect to the total weight of monomers (A),(B), (C) and (D) present in the composition.
 7. Composition according toclaim 1, wherein the polythiol monomer (C) has the formula R₁(SH)_(n) ¹,in which n¹ is an integer of 2 or more, and R₁ is an aliphatic oraromatic radical.
 8. Composition according to claim 1, wherein thepolythiol monomer (C) represents 10 to 60%, by weight with respect tothe total weight of polymerizable monomers present in the composition.9. Composition according to claim 1, characterized in that the othercopolymerizable monomers (D) are chosen from monomers of formula:

in which R₅ represents H or CH₃ and m₂+n₂ has a mean value from 0 to 20inclusive.
 10. Composition according to claim 1, characterized in thatthe other copolymerizable monomers (D) represent 0 to 60% by weight ofpolymerizable monomers present in the composition.
 11. Optical lensobtained by polymerization of a composition according to claim
 1. 12.Optical lens according to claim 11, wherein the lens is an ophthalmiclens.
 13. Optical lens according to claim 12, wherein the lens is aspectacle glass.
 14. Composition according to claim 4, wherein Q is—CH₂—.
 15. Composition according to claim 6, wherein monomer (B)represents 10 to 40% by weight.
 16. Composition according to claim 7,wherein n¹ is an integer from 2 to
 5. 17. Composition according to claim8, wherein polythiol monomer (C) represents 10 to 60% by weight. 18.Composition according to claim 10, wherein other copolymerizablemonomers (D) represent 10 to 50% by weight.